Lawinenlagebericht

Swan Range

Flathead Avalanche Center
Auf der Karte ansehen

Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
Open full map
Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

Steady winds continue drifting fresh snowfall into small, thin slabs beneath ridgelines and in gullies. Identify them by their dune-shaped or pillow-like feature. Cracking in denser surface snow indicates instability, directing you to a lower-angle slope or one sheltered from the wind. 

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Moderate to strong west-to-southwest winds continue transporting surface snow into thin slabs. There has not been much snow for these winds to work with, but today's snowfall may aid in slab development. These features should be small and easy to avoid. They will be found just below ridgelines and saddles on the downwind side. Cross-loaded slopes and gullies also accumulate wind-drifted snow.  

    Blowing snow points in the direction of fresh slab development. Dune-shaped or pillow-like features identify areas of wind-drifted snow. Cracking in the snow surface indicates instability directing you to lower-angle or terrain sheltered from the wind. 

    (12/2/2024)

    This is an example of a small wind slab at a mid-slope location. Slabs tend to be larger and more dangerous near ridgeline elevations. 

    Photo: Flathead Avalanche Center

Avalanche Discussion

A storm system was expected to impact the Whitefish Range on Saturday and the Swan and the Flathead Range overnight. Unfortunately, this system underproduced with snowfall amounts in the 1-3 inch range, with 0.1-0.3 inches of water. This minor moisture did little to affect the avalanche danger or problems yesterday or overnight. 

Lingering precipitation today will add a bit of weight and stiffness to the slab resting on a layer of surface hoar in the Whitefish Range, Flathead Range, and Glacier Park. Most observations from these two zones report a surface slab that remains too soft to propagate (Observation 1, Observation 2). The exception would be in areas loaded by recent wind that stiffened the snow surface. The 12/7-12/8 warm, wet storm initiated multiple avalanches in the northern Whitefish Range but also rained to ridgeline elevations in the Swan Range and the Apgars. This rain destroyed the surface hoar, and we removed the Persistent Slab problem from those areas. 

We added a Wind Slab problem to the Swan Range on Saturday, expecting this problem to develop late in the day or overnight. That probably did not happen, but we will list this problem today in anticipation of developing light to moderate snowfall. West-to-southwest winds continue an impressive streak of strong average speeds with gale-force gusts at the Aeneas Ridge wind station. 

Did you hear about the app? You can now access our region's forecasts, observations, and weather data directly from the Avy App (IOS; Android). Many features are accessible offline, so you can win debates about the avalanche problems right in the backcountry or submit an obs while driving home. 

Are you looking for avalanche education opportunities? Check out our calendar for upcoming events. Tomorrow, Monday, December 16, there is an Avalanche Awareness Class at Bias Brewing.

Abgedeckte Regionen